Desuperheater control



J. M. BARRETT DESUPERHEATER CONTROL Oct. 16, 1928.

Filed Jan. 5, 1927 Patented Oct. 16, 1928.

UNITED STATES ATENT oer-ice.

JOSEPH a. masses, or rosronm. onto, reassessment swati'rwourooivrrhivir, OF CLEVELAND, OHIO, A CORPORATION or 01110.

'DEsuPERHEATsR censor.

Application med January 3, 192 Serial No.'158, 590.

This invention relates to desuperheatii'ig and is particularly concernedwith 'thecontroloi. the change in quality of steam by reason of the flowof water to the desup'erheater. p

It frequently happens in steam power plants that the steam deliveredfrom the boiler or boilers is superheated several hundredrlegrees' Italso happens that it is desired to use only saturated steam or at leaststeam that is but slightly superheated, for the auxiliary apparatus orfor carrying out certain processes where thesuperheatisdisadyantag'eou's or even harmful. I

' The method of desuperhcating steam, shown in the disclosure herewithcomprises spraying comparatively cold water under high pressure into achamber through which the steam passes. The superheated steam picks upthe moisture, vaporizes it and delivers substantially saturated steam.The

quality or tlierelative amount of superheat in the steam delivered fromthe chamber depends upon the rate of flow of water into the chamber.

The design of a given desuperheater estab lishes certaiirconstantfactors but, for the purpose of showing my invention, I presume that thespraying and bathing apparatus'in the chan'lber is such that for steamof a given degree oi superheat, if water is trapped at a certainrateimmediately below the chamber that substantially saturated steam will bedelivered. I V

It is among the objects of my invention to control the low of water intothe desuperheater so that acertain amount of water will be inaintaii'iedin a container or receiver dis-' posed below the chamber and in freecommunication therewith. By so doing, predetermined amount of water isaddedto the superheated steam so that saturated steam is delivered. Theamount of water then held in the, container below the desuperheatingchamber is a measure of the quality oi the steam deliveredi It will beseen that if the inflow of water is stopped, that the superheated steamwill pick up all the water with which it comes in contact so that boththe .desuperheating chamber and the ad jacent container or receiver willbe quickly dried. i

To accomplish the objects of myinvcntion, I control the flow of waterinto the desuperheater with relation to the amount of water maintainedin the receiver iimnediate'ly below the chamber and thereby 'ac"complishing the result of delivering substantially saturated steam. Asthe demand for saturated steam varies, the inflow 0t superheated steamwill vary accordingly, therefore, it is necessary toproportion theinflow ofwater to the desuperheater so that a certain'quality ofdelivered steam may be maintained. I am able to accomplish this resultby controlling the inflow of water into t-l1edesuperl1eater by using asa-m'e'astu'e'lthe amount or" water in the receiver disposed below thechamber. V v

If by reason of the primary demandon the boiler, the degree of s'uperheat varies, and I desire to deliver steam of the same quality fromthe desuperheater, I find that by controlling the inflow of water withrelation to the amount of water'h'eld in the con tainer below thechamber, that I may compensate for varying degrees of superheat as Wellas for demand for saturated steam.

.Thus I am able by very simple installation to accurately and constantlycontrol the input of water so that steam: of a certain predeterminedquality will always'be delivered regardless of the degree of superheatorthe demand for saturated steam. I

j Other objects will become apparent from the following more detailed(ilescriptioh of the apparatus employed in my invention, a preferredform of which is shown in the drawings. The essential characteristicsare summarized in the claims.

In the drawings Fig. 1 is an elevation water. inlet at 10, I showdiaphragm closed by the spring 11 and which is forced to open positionas a result of pressure eX- erted on the diaphragm 12 through theconduit 15 by means presently to be described.

As mentioned above, a container. or receiver 40 is disposed immediatelybelow the desuperheater 1 in free communication therewith through theshor"u connection a1, a gauge glass may be used as at 42 to show thewater level LL in the receiver 40. A suitable blow-oft valve 13 may beconnected to the bottom of the receiverso that an occasional collectionof sludge or mud may be blown down.

Disposed to intersect the plane of the water level of the receiver, Ishow a pressure generator 20, having radiating finsr18- and a filingplug 19 This generator may be of general type shown in the patent toCopley No. 1,193,125 issued August 1, 1916.

The generator is mounted on a conduitw iich The generator is connectedat its lowermost point with the pressure conduit 15 mentioned abovewhich leads to the diaphragm chamber of the valve 10. It will be seentherefore, that when the water level in the receiver rises that thegenerator will be chilled and the pressure in the conduit 15 and onthe-diaphragm l2 reduced so that the valve 10 will be forced to a closedposition. On the other hand, when the water level in the receiver falls,the steam will move downwardly adjacent the generator thus building upthe presure of the working fluid therein, which will tend to open thevalve lOto permit a greater inflow of water so that a substantially evenWater level is maintained with theresult that the proper amount of wateris introduced to the superheated, steam so that saturated steam will bedelivered.

To efi ect the operation of the pressure 7 generator, I provide the.conduit 21 which I show connected at its upper extremity through thevalve 22 to the superheated steam inlet pipe at the point '23. I find 1tadvantageous to connect the conduit 21 either. tov the superheatedsteaminlet or the saturated steam outlet rather than any part of thedesuperheater or the receiver because vofthe preseneeof water or'mist inthe last named chambers. It is however, possible butnot so practical,toconnect the upper portion ofthe conduit 21 to the de superheater with asuitable. trap .connec tion so that the steam in this portion of theconduit 21 is substantially dry. The conduit point 30, and by reason ofthe connections 24,25 and 26, the angular position of the generator maybe varied. It will be seen that the rapidity of reaction of thegenerator is a function of its angular position.

Associated withthe portion 32 of the conduit' 21, which portion isimmediately below the generator, I provide a radiator or cooler 33. Thisradiator also serves as a cold water reservoir. The cooler may for thesake of convenience, be of a construction similar to the generatorproper (see Fig. 3), but the connection with the portion 32 of theconduit is such that water may flow through the whole cooler having. anopportunity to pass through the chamber adjacent the heat radiating fins3 L as shown. A plug 32' is put in the conduit; perforations 35 areprovided; A suitable blow-down valve 36 is connected to the lowermostportion of the conduit 21 so that the contents of the conduit may beblown out when desired. It is adwhich will tend to open the valve 10 andlet water flow into the'desuperheater. If the valve is forced wide openby reasonof high pressure being exerted, a surplus of water will collectin. the receiver 40 so that the water level in the receiver will rise-.until that portion of the conduit 21 within the generator containswater'o'l a low heat con tent which will tend to chill the generator andthrottle the valve 10 sothat the inflow of water is balanced against thedemand therefor.

. Particularly in starting, it isfound that the water. collecting in thereceiver is very hot in that the generator may be very slow to respondto a rapidly rising water level. By the use of the radiator'or cooler 33I am able to chill all of the water. which moves upwardly into contactwith the generator so that the temperature difference may be sharp andthe action of the generator well defined;

The drop leg construction including the portions 31 and 32 of theconduit 21 along with the cooler 33, provides for the maintenance of areservoirof cold water even in the event that all the water in the.receiver is taken up. It will be seen that I. gain added advantages byusing both the'drop leg and cooler. I

From the foregoing it. will appear that I have provided a simple andrugged control for a desuperheater, that my device can be oper dadvantageously on high pressure tions and that the wearing and WOIliing)2 ts are very few, and thatthe operation constant and positive; Thequality of the steam delivered may be controlledby reason of thecompensation effected both :for

the degree of superheat and for the demand for saturated steam,

I claim: p

1. The method of controlling the flow of water to a desuperheaterdependent upon the rate of accumulation of water collected 3. Incombination, a desuperheater, a rcceiver disposed below the-desuperheater and in open communication therewith but protected fromthe flow of steam through the desuperheater and means controlling theflow of water into the desuperheater depen dent upon the water level. inthe receiver.

4.. The combination witha desuperheater, a receiver disposed below thedesuperheater, means for controlling the flow of water to thedesuperheater according to the water level in the said receiver, saidmeans includinn; thermo-responsive means disposed at the water level ofthe receiver.

5. In combination, a desuperheater having an inlet for superheatedsteam, an outlet for saturated steam, a Water pipe for delivering waterto the desuperheater, a valve in said pipe, a receiver positioned belowthe desuperheater adaptedito contain an excess of water delivered to thesaid desuperheat-er, and thermo-responsive means responsive to change ofwater level in the receiver for actuating said'valve. V

6. In combination, a desuperheater having an inlet for superheatedsteam, an outlet'for saturated steam, a water pipe for delivering Waterto the desuperheater, a valve in said pipe, means for maintaining anexcess of water in the presence of the steam, and thermo-responsivemeans respon- V sive to change in the amount of said excess water foractuating the valve in said Water inlet pipe.

7 In combination, a desujperheater liavmg an inlet for superheatedsteam, an outlet tor saturated steam, a water pipe for delivering waterto the desuperheater, a

pressure actuated valve in said pipe, a receiv'er positioned below thedesuperheater r. .ited to contain anexccss of water delivered to thesaid, des-upcrheater, a conduit connected to said receiver and to saidsteam inlet and pressure generator means associated with saidconduitresponsive to change of waterlevel in the receiver for, varyingthe opening ot'said valve.

eluding a mixing chamber having an inlet for superheated steam and anoutlet for saturated steam, a water pipe leading to said desuperheater,a valve in said pipe, means comprising a separate chamber formaintaining below the desuperheater an excess of water in open contactwith the steam, and means for varying the opening of said valvedependent upon the amount of said excess. 9. In combination, adesuperheater having an inlet for superheated steam and an out-- let forsaturated steam, a water inlet pipe connected to the desuperheater, apressure actuated valve in said pipe, a conduit disposed outside ofthedesuperheater and connected at its ends to different parts of thedesuperheater, and pressure generator means associated with said conduitfor controlling the opening of said valve.

10. The combination of a desuperheater having an inlet for superheatedsteam and an outlet for saturated steam, a Water inlet pipe for thedesuperheateig a valve in said pipe, a receiver positioned below thedesuperheater and in open communication therewith, and adapted tocontain an excess of water delivered to the desuperheater, a conduitleading from a point in the receiver below the normal water levelthereof, and to the steam inlet, pressure generator means associatedwith the conduit and positioned in the plane of the normal water levelof the receiver, said conduit including a drop leg between the saidpressure generator means and the receiver, radiating and cooling meansassociated with the conduit beloW said pressure generatonand fluidconducting means connecting the pressure generator with said valvewhereby the valve is actuated in response to change in water level insaid receiver.

11. The combination of a desuperheater having an inlet for superheatedsteam and an outlet for saturated steam, a water inlet pipe, a receiverpositioned below the desuperheater and in open communication therewithand adapted to contain an excess of water delivered thereto, a conduitconnected to the receiver below the normal water level thereof and to apart of the system containing 8. The combination ota desu'perheaterinpipe for the desuperheater, a valvein said dry steam, pressuregenerator means associat'ed with the conduit and positioned in the planeof the normal water level of the receiver, said conduit including a dropleg between the said pressure generator means and the connection withthe receiver, radiating and cooling means added to and associated withthe drop leg portion adjacent said generator, and means connecting thepressure generator with said valve whereby the valve is actuated inresponse to change in Water level in said receiver.

12; The combination of a. desuperheater having an inlet for superheatedsteam and an outlet for saturated steam, a water inlet pipe for thedesuperheater, a pressure actuated valve in said pipe, a receiverpositioned below the desuperheater and in open communication therewithand adapted to contain an excess of water delivered to thedesuperheater, a conduit spanning the normal water level of the receiverand connected to the inlet for superheated steam, pressure generatormeans responsive to change in heat content of the fluid 1n the conduitfor actuating said valve and positioned in the plane of the normal waterlevel of the receiver, said conduit including a drop leg portion belowthesaid pressure generator quickly responsive to change in Water levelin the receiver.

In testnnony whereof, I hereunto affix my signature.

JOSEPH M. BARRETT.

